Female pseudohermaphroditism is an intersexual state distinguished by virilized external genitals and secondary sex characters in a XX subject. We report a case of female pseudohermaphroditism diagnosed later on the discovery of an abdominal mass, then revealed to be an enormous ovarian cyst. Hormonal dosages suggested the presence of partial surrenalic b-hydroxylase deficiency. For this reason the clinical picture was considered expression of an adreno-genital syndrome, displayed as female pseudohermaphroditism with Prader stage V virilization.